


I'll have your back, If you'll have ours

by mm8



Category: Sherlock (TV)
Genre: Anal Fingering, Anal Sex, Angst, Barebacking, Blow Jobs, Creampie, Dirty Talk, Emotional Hurt/Comfort, Established Relationship, F/M, Hurt/Comfort, Jealousy, M/M, Oral Sex, Polyamory, Size Kink, Smut, Spitroasting, Threesome, Threesome - F/M/M
Language: English
Status: Completed
Published: 2014-07-01
Updated: 2014-07-01
Packaged: 2018-02-04 10:06:01
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,057
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1775215
Author URL: https://archiveofourown.org/users/mm8/pseuds/mm8
Summary: <blockquote class="userstuff">
              <p>John had only been to work for a couple hours when he received a three texts from Mary:</p><blockquote>
  <p>Baker ST.</p>
</blockquote><blockquote>
  <p>Come now, please.</p>
</blockquote><blockquote>
  <p>Sherlock emergency.</p>
</blockquote>
            </blockquote>





	I'll have your back, If you'll have ours

**Author's Note:**

  * For [billiethepoet](https://archiveofourown.org/users/billiethepoet/gifts).



> Baker ST.

> Come now, please.

> Sherlock emergency.

John grimaced at his mobile's screen. It was only… Christ, it was only half past ten. When he waved goodbye two hours ago, Mary and Sherlock had barely noticed. The pair had been poring over wedding plans. Exactly what details they were working on, he wasn't sure. 

John's eyes still felt bleary after staring at all the color combinations for the save-the-date postcards. Before yesterday, blue was blue. It had been that simple. Sherlock and Mary were so shocked at his blandness that they immediately hauled him off to the nearest hardware store to assault him with tiny plastic cards with different color shades that people used when they wanted to paint their houses. His lovers were so excited that there was a shade of blue on the color palette named St. Bart's. After the owner threatened to throw them all out if they didn't buy something, Mary smiled warmly at him and insisted they buy at least two cans of paint. John argued that they didn't need any paint in the near future. Sherlock just smiled at him knowingly, the right side of his lip curled upwards and said _"You never know when paint can come in handy, John."_

Perhaps that was what they were doing when he left. Looking at more blasted shades of blue for the save-the-date. They both should have still been in bed, he thought lazily. Mary had a day off and Sherlock could pick and choose his days. He yawned and stretched his arms upwards towards the sky. It was raining today and his bones ached which made everything worse. 

He stopped mid-stretch as his phone vibrated in his hand. He lowered his arms and tapped the screen to refresh it.

> Don't make me beg.

Well, that was it, wasn't it? He took coat off the hanger and grabbed his duffle bag stuffed with the clothes he had packed for their weekend stay at Baker Street. 

"Taking my lunch break early, Georgia," he informed the receptionist as he breezed by. "Just split all my patients between Dr. Patel and Dr. Melnyk, yeah?"

He didn't bother to look back to scold Georgia for her giggling with the comment _"More like a quickie…"_

He sent a short text off to Mary.

> On my way.  
>  -jw

A million things went through his mind as he took the tube toward Baker Street. A Sherlock emergency could mean anything really. There was no more coffee in the flat. He'd received an email from a child asking him to solve a case of why the burgers their mother made were so salty. Or God forbid that Mycroft had popped by. 

At least the tube ride had been decent. No one sat near him probably due to the serious expression on his face. When the train stopped, he was the first off, eager to see what his lovers had gotten up to. John was able to breeze down Baker Street with no trouble. It wasn't too crowded at this time of day. 

The knocker on the door of 221 was tilted to the side when he marched up the street. No Mycroft then. Quickly, John fished out his keys from his jacket pocket and jogged up the stairs to the flat. He stopped dead on the last step. The door to the flat was ajar; the sweet smell of Mary's cranberry orange bread wafting through the air. He took a deep breath and entered the flat, closing the door softly behind him.

The place seemed empty at first. The living room was clean, or as clean as it could be with Sherlock. The tray of tea and biscuits that Mrs. Hudson delivered every morning was still on the coffee table. Mary's own weekend getaway bag was resting on the arm of the couch. It lay open, as though Mary had put it there then wanted to take out something, and just forgot to button it back up. The television set was on and set to BBC One, the volume barely audible. Walking softly across the floorboards, he set his duffle bag down on his chair. He wondered where everybody was and why it was so quiet. It was really eerie. As John turned to find the remote to the TV, he stepped on a squeaky board, announcing his presence. 

Mary popped her head around the corner from the kitchen. "Oh good, you're here." She was a mess, her eyes puffy and red-rimmed, and tiny lines of mascara ran down her cheeks. When he'd left for work this morning, his fiancée's hair had been brushed and pulled back to the side with a hair clip. Now the clip was gone, her hair was frizzy and sticking up in odd places. Mary rushed forward and wrapped her arms around his shoulders. John pressed against her, Mary's breasts flush alongside his body. He slotted his face against her neck and inhaled. She wasn't wearing her usual Claire-de-la-Lune. This was Mary's natural scent and it was much better than any perfume. 

When Mary let go, she sniffled and wiped her eyes with the back of her hand. "I'm not sure what happened. We were fine. Drinking some coffee and looking over some fonts for the save-the-dates. You had only been gone for an hour or so, I think. I noticed the time and remembered how I had a brunch date with Kate and said I ought to be going. Then he just, he just," she flitted her hands in front of John's face. 

He looked at her skeptically, rearing his head back and narrowed his eyes. "Wha-what do you mean? Did he yell? Did he pace obsessively? Did he throw things about?"

Mary shook her head. "No, nothing. He stared at me blankly for a moment. Then got up, went to his room and hasn't come out since. He even locked the door! I tried to follow after him, but he had already locked himself in. I kept knocking and pleading with him… But," she threw up her hands. 

"And yet you had time to bake your mother's famous award-winning cranberry-orange bread?"

She shrugged. "I got bored. It's done if you want any."

The doctor rolled his eyes. "How did he have any edible ingredients lying about?" John asked as he traveled over the sofa and crouched down beside it. 

"I may have restocked his kitchen a couple weekends ago…" She smiled with her eyes. "Frankly, I'm surprised everything hasn't been used for experiments yet. What are you doing anyway?"

Gently, he lifted up the floorboard to the right of the couch leg. "Aha," he said triumphantly when it gave. He pulled out a set of lock picking tools and waved them at Mary. Without waiting for a reply, he got up and went to Sherlock's door at the end of the hall. His legs protested when he bent down again to insert the tools into the lock, his ear pressed against the door.

"You know how to pick locks?" Mary asked, suddenly beside him. 

John hummed. "You learn a lot of tricks when you spend time with Sherlock." He smiled up at his fiancée and winked. 

"Do you think we should be breaking into his room like this? You know, privacy and all that?"

"Does this bother you?" he asked without stopping his task.

"No. Kind of makes you look sexy," she flirted.

John flushed a bit under the scrutiny. "Almost there," he murmured. "You tried being reasonable with him and that didn't work. Now it's time for other tactics. Besides, think of it as Sherlock getting his own medicine for all the times he's come into my room in the middle of the night to talk theories while jumping on my bed or to play his violin. Ah!" John exclaimed. "Got it!" He twisted the knob and the door swung open. 

"Sherlock?" he asked timidly as Mary helped pull him to his feet. "Mate, are you alright?"

"Oh," Sherlock said spitefully. "You're here. Thought you'd have gone by now." There was a short pause. "No. After Mary stopped harassing me through the door, she felt flustered, playing with her hair. She... she cried," his voice waivered. "She shouldn't have done that." He shook his head, taking a drag from his cigarette before continuing. "She wasn't sure what else to do. She texted you and pleaded that you come over to set me straight." He chuckled drily. "You didn't reply immediately because you had barely been at the clinic for a couple hours. But when Mary's texts became insistent you rushed right over. Mary had time to kill until you arrived. She didn't want to clean the flat, what else was there for her to clean; she had done that a couple of weekends ago? And she is smart enough not to mess with my experiments, unlike you and Mrs. Hudson. The crap they put on BBC One on Monday mornings bored her to death so she put it on low for some background noise. Finding that the food she had stocked in my kitchen had been undisturbed-- and why would I eat cranberries? She set to work making her mother's award-winning cranberry orange bread to pass the time until you arrived."

Mary and John exchanged glances. Even in his black mood, their lover could still get everything right. Cautiously, they stepped foot into Sherlock's bedroom. The great man was standing by his open window, leaning over the windowsill and smoking a cigarette in the humid London air. He was shirtless, his back to them. All he wore was his pair of black trousers that John saw him wear earlier in the day. Even his feet were bare. Sherlock looked vulnerable. His head sticking out of the window, the wind rustling through his black curls, his ankles crossed casually. To John he looked like an average teenager sneaking a smoke out of the bedroom window behind his parents' backs. 

"Sherlock, it's still raining. Why do you have the window open? You're going to catch a cold," Mary said with concern. 

"I would expect a nurse to know that one cannot catch the common cold from water falling from the sky," Sherlock replied, his back still facing them. 

Mary rushed over to their lover, but as soon as her hand brushed Sherlock shoulder, the detective brashly slapped it away. "Clear off," he gritted through teeth clenched around his cigarette. 

"Hey!" John strode over the other side of the stroppy detective. "What the hell is going on, Sherlock?" He glanced over to the bin below the window. "Fuck!"

"What is it?" Mary asked quizzically, her gaze shifting back and forth between Sherlock and John, her eyes threatening to flood over with tears.

John bent over and picked up two empty cigarette packs and held them up. "Jesus, have you been chain-smoking in here for the last hour?"

"No," Sherlock deadpanned. He crushed his lit cigarette on the edge of the windowsill, flicking the stub into the open window. He easily pulled out another one from a pack that rested beside his elbow and lit it, taking a long, smooth drag. 

"Fuck, Sherlock!" John cursed. "How many is that? At least 41?"

"41?" Sherlock scoffed. "Please, I think you drastically overestimate my ability to smoke. 32. First pack was half empty and I just started this one. Hey!"

John snatched the cigarette from Sherlock's pale fingers and tossed it out the window into the street below. Mary followed by closing and locking the window. 

Sherlock threw him an angry look. "I wasn't finished with that!"

John grabbed Sherlock by his shoulders and shoved him into a sitting position on the bed. "Yes, you bloody well are!" He nodded to Mary as he sat on Sherlock's left, and immediately she sat his other side boxing him in. The doctor grasped Sherlock's chin to make him look straight at him. "We're all going to sit down and _talk_ about what is bothering us like adults." He pulled Sherlock's face closer. "And if you ever touch Mary like that again, I swear Sherlock Holmes, that I will cut you into so many tiny pieces that not even your brother will be able to find you."

"Would you do it for me?" Sherlock whispered, eyes downcast.

Mary let out a tiny gasp. John met her gaze for a second before directing his attention back to Sherlock. "What do you mean? I just said—"

"No dumb-dumb," Mary scolded him. "The other way round."

John furrowed his brow. The other way round? The other way round… What did that mean? The other way round from Sherlock hitting Mary? From him protecting Mary… oh, that was it.

"Yeah, he gets it now," Mary commented. "Just look at how his eyes lit up. Bit slow on the uptake sometimes, our John." She nudged her shoulder with Sherlock's. 

John held his lover's face and drew him in close. "Sherlock, that is the most ridiculous question I have ever heard come out of your mouth." He brushed his fingertips over the corners of his lover's pale lips. "I love you and Mary equally, Sherlock. I would do anything for both of you. Anything. That means protecting you if Mary hurts you and visa versa. Don't you feel the same for us?"

Sherlock nodded meekly.

"But that isn't the real problem, is it?" Mary suggested softly, grasping one of Sherlock's hands.

The detective shook his head, keeping his eyes away from either of them. "Just the tip of the iceberg, I'm afraid."

John watched as Mary took control of the conversation. The doctor let go of Sherlock's face, handing over that honor to his fiancée while John placed his hand on small of Sherlock's back. Mary stroked their lover's cheek with her thumb, and leaned in so their foreheads touched. 

"What happened, Sherlock? What's wrong?" She nuzzled his neck and the detective instinctively leaned into the touch. "Why did you shut me out? John and I love you, Sherlock. You are so brilliant, wonderful and caring--and don't you dare think that you aren't!" she added when Sherlock scoffed. "We love you so much. We'll never leave—"

"You will," Sherlock interrupted. "You do."

John stared at the back of Sherlock's head memorized. Sherlock's shoulders were slumped low, his position atrocious compared to his usual perfect posture. What on earth did Sherlock mean? Leave him? They were together right now, weren't they? 

Bloody hell, if anyone was to talk about who left who it should be John. They had a solid thing going on before the Sherlock jumped. John had grieved the loss of his lover, lived in a black cloud for the better part of a year. Then one day, one of the nurses didn't show up for work. When they looked into things, they discovered she'd had a heart attack at her flat over the weekend. Mary was hired as her replacement, and on her first day she asked John to sit with her during their lunch break, not taking no for answer. They hit it off and the rest was history, until Sherlock popped back into their lives saying, _''Allo, I am not dead'_.

John thought hard. Christ, was this about all the weekend stay-overs? Sherlock did seem to falter when Mary mentioned she had to go. But this arrangement had been going on for a couple months already. What was bothering him about it now? Had he watched some crap telly in his spare time and got some crazy idea stuck in his head that they only stayed the weekend for booty calls? Did someone say something offhand to him? Lestrade? Mrs. Hudson? If it was Mycroft, John was going straight to James Street and punch that bastard right in his— 

"Sherlock, darling," she lifted her head to speak directly at the detective. "When you came back, I was charmed by you. You were…" Mary sighed. "Everything that John said you were. And it scared me. You fit together so perfectly, so beautifully. You work. Even after that first night and all John could do was punch you," she giggled. "I could see it. The spark between you. I felt jealous. I was worried that since you were back, John would just cast me aside."

"Never," the men stated together. John gazed sidelong at Sherlock, who was still staring intently at Mary. 

She reared back her head and laughed. "See? That's what I am getting at. Darling," she ran a hand through his curly locks. "You have nothing to worry about. When we, the three of us, started this, we mutually agreed to never let go." 

Mary began trailing kisses down Sherlock's long jaw. The detective visibly relaxed, closing his eyes and sighing. John took his fiancée's cue and began to stroke the inside of Sherlock's thigh. The man moaned as he opened his legs wider to give John more access. The doctor's own cock began to stir to life. He enjoyed seeing Sherlock simply surrender to them.

"Our weekends with you, mean the world to us," Mary whispered between kisses. She sucked hard on the crook of Sherlock's neck, eliciting a quiet moan from the man. Her fingers roamed his bare chest, flicking his pink nipples. "We can turn everything off and finally _be_ with you. It's—"

"Bliss," John supplied. He slowly unzipped Sherlock's black trousers and pulled out his cock. It was already half-hard. It was such a lovely dick. When completely erect, would be quite veiny and Jesus, John loved that. It was not as thick as John's, but about the same length, still big enough to be considered huge. It was certainly the biggest dick that John had ever seen besides himself. John pulled the foreskin back, revealing the beautiful head. Pre-cum began to leak out of the tip. The blond lazily stroked Sherlock to full hardness. 

"We want to be with you," John breathed huskily. "All of us, together. Even though Mary and I are getting married, that won't change what's between the three of us. It never will." He licked up the long column of Sherlock's neck and paused at his ear. Oh, the noise that came out of his lover's mouth. "I will spend every day of the rest of life making sure you get that through your thick, magnificent, beautiful skull." 

Sherlock lifted his hips and shimmed out of his trousers and pants. "You two are wearing far too many clothes."

John shot up, quickly discarding his shirt, shoes and socks. He was working on his zipper when he heard the detective moan. John let out a groan when he saw his fiancée naked and knelt on the floor between Sherlock's legs vigorously taking his large member in her mouth. "Christ," John said as he kicked off his trousers, tossing them to the side where Mary's sundress and lingerie lay. He hooked his thumbs under the band of his red pants, pulling them down his legs. He pumped his own cock as he watched Mary swallow all of Sherlock's dick, gagging as it hit the back of her throat. The detective gave little shallow thrusts into her mouth. 

John crawled onto the bed, pushing Sherlock on his back. He gave his lover a messy, filthy kiss, all spit, teeth and tongue. Sherlock tasted of wood and smoke, he thought off-hand. When John pulled back he immediately put in prick between Sherlock's pretty lips. The detective eagerly began to suck at the head of John's cut cock, fisting the rest of the thick shaft. "You're both such good cock suckers," he groaned. John couldn't help but smile when they both moaned loudly in response.

There was a wet sloppy pop as Mary took out Sherlock's erection. Her eyes met her fiancé's. They nodded to one another. 

John released the detective's grip on his arousal. Sherlock pouted up at him, missing the loss. A second later, his eyes widened and he let out a loud gasp. The ex-solider took the opportunity to fill his lover's mouth with cock. He held onto Sherlock's curls and thrust gently. He glanced sideways at Mary. She was squatting on top of the detective's leg, his long dick already halfway inside of her pussy. 

"You'll have us, Sherlock?" John asked as he pulled back his large member from his lover's sweet mouth. "Both of us?"

"As long as you both will have me," Sherlock replied.

The doctor roughly tugged on Sherlock's hair so his lover's grey eyes stared up at him. "You'll never doubt us again?" John knew this was a futile request. He couldn't control Sherlock's anxiety any more than Sherlock could. But in the heat of the moment, all three of them needed to hear the words.

It took a moment for Sherlock to formulate the words—between the serious discussion he was having with John, and Mary fucking herself on his cock, the ex-solider figured that it was quite distracting to express what he needed to. But he finally Sherlock breathed, "I can't always control my fears and doubts, John, but I'll try."

John swept away Sherlock's hair from his face. "That's all we can ask," he said, giving him a gentle kiss on his forehead. "Love you," he whispered as he stole a brief kiss against the detective's trembling lips.

"I think you should put that massive cock of yours to work, love," Mary panted as she slid all the way down Sherlock's prick. "His arse looks a bit lonely, don't you think?"

"Yes," Sherlock begged. "Yes, God! Yes. Please…"

John smiled wickedly. "Yes, he's earned it." He clambered off the bed and got the tube of lubricant from the top of the nightstand. He put some of the goop onto his fingers and was easily able to stretch Sherlock with two fingers straight away. His lover's hole was still somewhat loose from their coupling the night before. It didn't take long until he was adding a third to the mix before the detective was shouting at him to "hurry it up, for God's sake, John!"

The ex-solider couldn't help but laugh as he applied a generous amount of lube to his dick. He gripped Mary's curves, making print marks on her sparrow tattoo as he plunged deep into Sherlock's arse. He moaned and thrust rapidly, bottoming out. The slapping sound of skin against skin was obscene. It was hot inside of Sherlock. The man seemed to squeeze around his cock as he moved. It was so sweet. 

John moved his hands up and cupped Mary's bouncing breasts, pinching her erect nipples. Mary squealed as she rode Sherlock's big dick. Her dominant hand was busy circling her clit. Her screams rose to a crescendo, echoing throughout the flat as she came with brute force. 

Sherlock wasn't too far long behind her. His right arm covered face, muffling his cry as he painted the walls of his lover's cunt with his seed. Mary tilted her head back, moaning wantonly. "God, it's so warm. Fuck." Slowly, she lifted herself Sherlock's long dick. His pearly cum dribbling out of her vagina. Mary lay boneless beside Sherlock, her legs spread wide. 

John could tell he was close. He withdrew from Sherlock's tight heat, and pushed the head of his cock into Mary. He stroked his dick a couple times before adding his own sperm along with Sherlock's inside his fiancée's pussy. He cursed, relishing in the feeling of Mary's messy wet cunt, "Damn, fuck, you sloppy whore. I love you." As John pulled out, droplets of cum oozed out of Mary's used hole and down towards her ass. He suppressed a groan at the sight. His fiancée was filled and covered with his and Sherlock's cum. It was gorgeous. 

John collapsed on Sherlock's other side. As his breathing leveled out, he turned on his side, curling his fingers through Sherlock's hair. Mary mimed his movements as well, one of her legs twisted around the detective's. 

He kissed Sherlock's cheek. "We all better now?"

The detective hummed, his fingers crossed on top of his flat stomach. "Chinese?"

"Nope," John sat up. "I have to get back to the clinic. I've been gone far too long." He caught Mary and Sherlock's identical expressions of skepticism. "Speedy's?"

Mary grinned. "Done."

"Indeed," Sherlock agreed, closing his eyes. "Done."

**Author's Note:**

> I always forget to add this.  
> Follow me on tumblr-[mm8fic](http://mm8fic.tumblr.com/)  
> 


End file.
